A Philadelphia priest convicted of a sex crime involving a 10-year-old boy has died while awaiting appeal , his church said Tuesday .

The Rev. Charles Engelhardt , who was a priest at St. Jerome Parish in northeast Philadelphia , died Saturday of multi-system organ failure and a complete heart blockage at 67 , Father Kevin Nadolski said .

Engelhardt was in the process of appealing his sentence of 6 to 12 years in prison , stemming from his conviction relating to the indecent assault of a 10-year-old boy in the late 1990s . He was also convicted of endangering the welfare of a child , corruption of a minor , and conspiracy .

The Superior Court of Pennsylvania granted and heard arguments from Engelhardt last month as part of his year-and-a-half appeals process .

He has maintained his innocence throughout the trial and appeal , having pleaded not guilty to sexual abuse and conspiracy charges back in 2011 . `` I continue to believe that he 's completely innocent , '' Father Nadolski said .

Englehardt 's victim , now in his 20s , reported to authorities in 2009 that he was sexually abused while he was in Catholic grade school by Engelhardt and other priests . A grand jury determined his allegations had merit , and the priests were subsequently charged and arrested . They were among dozens of Philadelphia priests accused of sex abuse in a grand jury report .

Philadelphia District Attorney Seth Williams said at the time of conviction that the prison sentence `` sends a clear message to sexual assault victims in Philadelphia . If you come forward , you will be heard , '' he said . Williams called the verdict `` just . ''

A parochial teacher , Bernard Shero , who authorities said raped the same boy in 2000 , was convicted of rape , attempted rape , involuntary deviant sexual intercourse , indecent sexual assault and other charges . He is still being held in the Houtzdale , Pennsylvania State Prison .

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A Philadelphia priest convicted of a sex crime involving a 10-year-old boy has died while awaiting appeal

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Charles Engelhardt had just voiced his appeal to the PA Superior Court last month

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Engelhardt was convicted of indecent assault in the late 1990s